Supercollimation of Light Beams by Axisymmetric Aperiodic Photonic Structures

Abstract

Efficient beam supercollimation is proposed and shown experimentally by axisymmetric aperiodic photonic structures. The structure consists of equidistant layers of concentric refraction index rings, with the transverse period of the rings varying from layer to layer along the structure. Numerically designed and optimized axisymmetric photonic structures are inscribed in silica glass by femtosecond pulses. Strong enhancement (more than by one order of magnitude) of the axial beam component is demonstrated, resulting in the record performance of the beam supercollimation.

MECSEL with dynamic transverse mode control

“…Other structures of interest are based on the geometry of concentric filters, producing insights that a multilayer structure is unnecessary. This is valid for the super-collimation effect 36,37 , where the effect can be reproduced only with a single grating and a mirror, comprising a virtual 3D structure 38 . The only requirement is that the interlayer spacing, or the optical roundtrip path between the grating and a mirror is only slightly detuned from the Talbot self-imaging distance 39 .…”